When my son was small, his favourite part of making these cookies was dabbing his thumb into the middle to make the indentation to be filled with jam. You can use thumbs or a small melon baller, which is recommended in the recipe. I would use a few different kinds so he could have some variety if he had more than one cookie at a time, just for fun. Fill them with whatever jam you enjoy most—I loved apricot or raspberry most of all.
2 1/2 cups flour
1/2 tsp baking powder
1 cup unsalted butter, softened
1 cup sugar
1/2 tsp salt
1 large egg
2 tsp vanilla
1 cup fruit jam
Pre-heat oven to 300 F.
Using an electric mixer, beat the butter until light and fluffy. Add the sugar and combine well. Scrape down the sides of the bowl, then add the egg and vanilla. Beat until well mixed.
In a separate bowl, whisk together the flour, baking powder, and salt. Add to the butter mixture and mix on low until the dough comes together. It should be fairly stiff.
Measure out the dough by scant tablespoons and roll into balls, placing them on a cookie sheet about 1 inch apart. Using a small melon baller or a rounded 1/2 tsp measuring spoon, carve out the center of each ball of dough. Don't scoop the whole way through. Fill each with a scant 1/2 tsp of jam.
Bake cookies for about 20 minutes. While they bake, the cookies will spread. Sometimes I find that there isn't enough jam in each, so I usually heat about another 1/2 cup jam on the stove until runny, and top up the cookies when they come out of the oven. Allow the cookies to sit on the pan for a few minutes to cool before you remove them to a wire rack to cool completely.
Makes about 4 dozen
Adapted from Mrs. Fields